fix: Fehlzeitenkalender in Templates

LehrerApp.Desktop/Views/Students/CreateLetterDialog.axaml

@@ -32,6 +32,10 @@
           <TextBlock Text="Kein aktueller Kontakt vorhanden." Classes="emptyhint"
                      IsVisible="{Binding HasNoContacts}"/>
         </StackPanel>
+        <StackPanel Spacing="4">
+          <TextBlock Text="Anrede *" FontSize="12" Opacity="0.7"/>
+          <TextBox Text="{Binding Anrede}" PlaceholderText="z.B. Sehr geehrte Frau Mustermann,"/>
+        </StackPanel>
         <Grid ColumnDefinitions="*,12,*">
           <StackPanel Grid.Column="0" Spacing="4">
             <TextBlock Text="Lerngruppe" FontSize="12" Opacity="0.7"/>
@@ -46,14 +50,20 @@
         </Grid>
         <Border IsVisible="{Binding UsesAttendanceAdvancedContent}" BorderBrush="{DynamicResource AppCardBorderBrush}"
                 BorderThickness="1" CornerRadius="6" Padding="12">
-          <Grid ColumnDefinitions="*,Auto">
-            <StackPanel Spacing="3">
-              <TextBlock Text="Anwesenheitsdaten im Brief" FontWeight="SemiBold"/>
-              <TextBlock Text="{Binding AttendanceCalendarSummary}" FontSize="12" Opacity="0.65"/>
-            </StackPanel>
-            <Button Grid.Column="1" Content="Konfigurieren …" Click="OnConfigureAttendanceCalendar"
-                    VerticalAlignment="Center"/>
-          </Grid>
+          <StackPanel Spacing="6">
+            <Grid ColumnDefinitions="*,Auto">
+              <StackPanel Spacing="3">
+                <TextBlock Text="Anwesenheitsdaten im Brief" FontWeight="SemiBold"/>
+                <TextBlock Text="{Binding AttendanceCalendarSummary}" FontSize="12" Opacity="0.65"/>
+              </StackPanel>
+              <Button Grid.Column="1" Content="Konfigurieren …" Click="OnConfigureAttendanceCalendar"
+                      IsEnabled="{Binding !IsRefreshingAttendanceData}" VerticalAlignment="Center"/>
+            </Grid>
+            <TextBlock Text="Aktualisiere WebUntis-Daten für den gewählten Zeitraum …" FontSize="12"
+                       Foreground="#6B7280" IsVisible="{Binding IsRefreshingAttendanceData}"/>
+            <TextBlock Text="{Binding AttendanceRefreshError}" FontSize="12" Foreground="#D97706" TextWrapping="Wrap"
+                       IsVisible="{Binding AttendanceRefreshError, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+          </StackPanel>
         </Border>
         <StackPanel Spacing="4">
           <TextBlock Text="Brieftext" FontSize="12" Opacity="0.7"/>